The best thing I learned on this site is to take the expander ball out of the sizing die for 357 sig. You can substitute the decapper from any straight walled set, as they don't have expanders.

You can get a chamfering tool just about anywhere, but an ordinary countersink bit will work just as well. When you take the expander plug out of the sizer, you really must chamfer cases to ease bullet seating.

If you continue to load with the expander ball in place, you are creating a potentially dangerous situation. When your bullets set-back in the case, due to insufficient neck tension, it can cause pressure spikes in your loads. These can actually be serious enough to blow your pistol up. So, clean up your act -- pronto!

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That I could be wrong is an eventuality that has not escaped me. I just painted the pictures as I saw them. I do not know how to do anything else. (Saint Elmer, 1955)